Much to the annoyance of parents who have to pay the credit card bills, in-app iPhone and iPad buys are popular with kids.

A typical scenario: your tot is playing with a game like “The Smurfs’ Village.” It’s free to download will keep the kid busy building a village where they can play with the famous blue cartoon characters.

The problem? To complete the Smurf village, your kid might want to add an extra, say, a wheelbarrow of Smurfberries.

That in-app purchase comes with a price tag of $59.99. Other extras are slightly cheaper – a bucket of Smurfberries costs $4.99, two bushels go for $11.99.

Tap Zoo, another kid-friendly app with in-app purchases.

Kelly Rummelhart found out just how busy landscaping with the Smurfs her 4-year-old son was when the bill came: he racked $66.88 in charges on her credit card without knowing what he was doing while playing the game on her iPad.

Smurf Village Creators Capcom Interactive say the situation is “lamentable” and have placed the following caveat in the game description:

PLEASE NOTE: Smurf Village is free to play, but charges real money for additional in-app content. You may lock out the ability to purchase in-app content by adjusting your device’s settings.

The statement is little consolation to parents, who see these apps as kid-bait scams. A look at the top-grossing apps in the iTunes store shows that six out of 10 are freebies with in-app purchases – another four of them are kid-friendly games.

If parents have logged in in the last 15 minutes, kids can easily buy these apps by accident. Some of them cost $100.

Apple defends its system, saying the password system is adequate. Spokeswoman Trudy Muller reminds parents that they can restrict in-app purchases.

Another thing to remember: contacting Apple and complaining usually leads to a refund. At least it did for the disgruntled parents in the AP story.